I agree with filex on one thing and that is things get really boring when you hit level 5.
So my suggestion is that we could have a monthly competition between level 5 organizations rewards should be something special , this competition can be for the most BRs/Turfs for gangs and maybe arrests for squads, there should be only one winner that keeps those rewards for the following month while another round of this competition is going on.
However i find the idea to reset gang levels completely stupid